The antonyms for the word "more undetailed" are "more detailed," "more specific," and "more elaborate." These words imply that there is a need for greater clarity, precision, and depth of information or knowledge. A less-undetailed piece of writing or verbal communication is likely to be more informative, insightful, and useful to the reader or listener. In contrast, a more undetailed or vague piece of communication can be frustrating, misleading, and confusing. Therefore, it is advisable to strive for clarity, specificity, and nuance in any form of communication to ensure that the message is well-understood, well-received, and has the intended impact.